Prediction on mechanical and microstructural behaviour of friction stir welded thin gauge aluminium-copper sheets

Friction stir welding [FSW] is a promising technique for joining various similar and dissimilar materials with an application of frictional heat source generated by a non-consumable rotating tool for achieving high quality welds. In this article, FSW process is focused on the development of micro-friction stir welding [μFSW], which is observed on very thin sectional materials of thickness 1000 μm [1 mm] or less. The joining of precipitation-hardened aluminium alloy to pure-copper sheets of 0.8 mm thickness each were carried out on a semi-automatic vertical milling machine using a zero-pin length tool configuration. A mild steel backing plate is designed for fixture mechanism to hold the welding sheets on machine. Weld-process parameters coded for tool-rotational speed, tool-travel speed and tool-plunge depth are examined for predicting better joint characteristics. Mechanical responses such as tensile strength, yield strength, percentage-elongation and micro-hardness are recorded for better weld joints at weld-nugget zone [WNZ] interface. Microstructural features are observed on achieved mechanical responses of welded joints using scanning electron microscope [SEM] and energy dispersive X-ray [EDX] analyzer.